The present invention relates generally to air dryers for use in air compressor systems.
U.S. Pat. No. 4,993,922 to Lauterbach et al. describes an air compressor unloader system that solved two problems which had persisted in the art of air compressor systems. In particular, the Lauterbach air compressor system acts to prevent significant amounts of oil from seeping around the compressor piston rings when the compressor is in its unloaded mode and also greatly reduces the horsepower used by the air compressor in its unloaded mode. These problems were solved by the inclusion of an isolation valve between the compressor and the air dryer such that the compressor could be isolated to form an air spring during its unloaded mode. At the same time, the pressurized air stored in the conduit between the air dryer as well as the pressurized air contained in the air dryer itself is purged through a spitter valve at the bottom of the air dryer during the system's unloading mode.
One concern of the Lauterbach et al. is the expense of the system due to the number parts, additional piping between the various components, and the increased complexity of the system as a whole. What is needed is an air compressor system that retains the advantages resulting from an "air spring" as taught by Lauterbach, but without the additional components and complexity of Lauterbach.